Conventional radar systems are commonly provided upon ships, for example, for identifying the presence of relatively moving objects with which the ship might collide. The conventional radar system incorporates an oscilloscope or scope generally in the form of a position plan indicator (PPI) upon which a luminous radial line sweeps over the area scanned by the radar and produces a bright spot on the screen at the location of any object which reflects the electromagnetic emanations from the set. Although this information is normally displayed on the scope of a radar set, the operator of a ship, for example, is under no obligation to take any action because of the identification of objects thereby, even though the information as to their presence and relative location is visually displayed. Further to conventional radar systems there have been developed a number of highly complex radar tracking systems; however, the complexity and cost of such systems normally precludes their use as an assistance to the operator of a ship, airplane, or the like.
There has been developed an automatic collision warning system, as shown in U.S. Pat. No. 3,660,846, which operates with a conventional radar system to automatically actuate an alarm system upon the location by the radar system of an object within a predetermined area. This then requires the operator of a ship or the like carrying the collision warning system to make some decision with regard to the located object. If, for example, the object is of no danger to the navigation of the ship, for example, the operator may merely deactivate the alarm; however, if the object is on a collision course, the operator would take some evasive action. This then forces upon the operator of a ship or the like the necessity of making a decision and taking some action with regard to any radar-detected object within some predetermined distance from the ship or the like carrying the system.
The present invention comprises an improvement upon the system of the above-noted U.S. Pat. No. 3,660,846 and reference is made thereto and art cited therein for further background of the present invention.
The system of the present invention provides automatic collision warning with numerous and substantial refinements and added capabilities over the system of the above-noted patent. In particular, the present invention provides a warning range zone of controllable depth and placement with a controllable azimuth sector width.